9,415 research outputs found
VLBI Observations of a Complete Sample of Radio Galaxies V. 3C346 and 4C31.04: two Unusual CSS Sources
We present observations at 1.7 and 8.4 GHz of two Compact Steep Spectrum
(CSS) sources from a complete sample of low-intermediate power radio galaxies.
3C346 shows an asymmetric structure with a one-sided ``jet'' and ``hot spot''.
Present observations suggest that the classification of this source as a CSS is
inappropriate, and that it is a common radio galaxy at a small angle to the
line of sight. Its properties are in agreement with the predictions of unified
schemes models. 4C31.04 shows more complex structure with the possibility of a
centrally located flat spectrum core in between two close lobes. We suggest
that this source could be a low redshift Compact Symmetric Object.Comment: 15 pages, LATEX, uuenconde ps figures To be published in the
Astrophysical Journal, October 20th issu
The Broad Line Radio Galaxy J2114+820
In the frame of the study of a new sample of large angular size radio
galaxies selected from the NRAO VLA Sky Survey, we have made radio observations
of J2114+820, a low power radio galaxy with an angular size of 6'. Its radio
structure basically consists of a prominent core, a jet directed in north-west
direction and two extended S-shaped lobes. We have also observed the optical
counterpart of J2114+820, a bright elliptical galaxy with a strong unresolved
central component. The optical spectrum shows broad emission lines. This fact,
together with its low radio power and FR-I type morphology, renders J2114+820 a
non-trivial object from the point of view of the current unification schemes of
radio loud active galactic nuclei.Comment: 6 pages, 5 figures. To appear in the proceedings of EVN/JIVE
Symposium No. 4, New Astronomy Reviews (eds. Garrett et al.
B2 1144+35: A Giant Low Power Radio Galaxy with Superluminal Motion
We report on centimeter VLA and VLBI observations of the giant, low power
radio galaxy 1144+35. These observations are sensitive to structures on scales
from less than 1 parsec to greater than 1 megaparsec. Diffuse steep spectrum
lobes on the megaparsec scale are consistent with an age of 10
years. On the parsec scale, a complex jet component is seen to move away from
the center of activity with an apparent velocity 2.7 h c. It shows
a central spine -- shear layer morphology. A faint parsec scale counterjet is
detected and an intrinsic jet velocity of 0.95 c and angle to the line of sight
of 25 are derived, consistent with an intrinsically symmetric ejection.
The central spine in the parsec scale jet is expected to move at a higher
velocity and a Lorentz factor 15 has been estimated near the
core.The age of this inner VLBI structure is 300 years. Assuming a
constant angle to the line-of-sight, the jet velocity is found to decrease from
0.95 c at 20 mas (32 pc on the plane of the sky) to 0.02 c at 15 arcsec (24 kpc
on the plane of the sky). These findings lend credence to the claim that (1)
even the jets of low power radio galaxies start out relativistic; and (2) these
jets are decelerated to subrelativistic velocities by the time they reach
kiloparsec scales.Comment: 21 pages, 16 separated figures. A version with figures and table in
the text is available at: ftp://terra.bo.cnr.it/papers/journals - it is a ps
gzipped file, named giovannini_apr99.gz (792kb) - ApJ in pres
- …